The present invention relates to power transmissions and, more particularly, to power transmissions that are program controlled so as to provide substantially enhanced flexibility in terms of control of a machine of the type that operates on a workpiece.
In a number of manufacturing operations, where a workpiece, which may be textile material, sheet material, such as metal, glass or plastic, or material handling apparatus, undergoes sequences of operations which may be repeated cyclically, a number of types of indexing mechanisms have been employed to move various mechanical elememts to carry out the sequence of operations on the workpiece. For example, in the carpet tufting field, it has been the practice to employ rotating cam surfaces to shift a needle bar to impress stitched patterns on a carpet backing. Likewise, in handling lumber and sheet metal, it is conventional to employ templates to carry out the function of guiding a tool through a series of mechanical motions to cut or otherwise form the workpiece, as desired.
In operations of the foregoing as well as other types, it has long been desired to expand the flexibility of the types of operations that can be effected by the work tool to correspondingly expand the variety of types of products that may be obtained thereby.
One manner of achieving this goal has been to resort to rather complicated and expensive modifications of existing machinery so as to render the machinery responsive to mechanically or electrically readable program sources such as magnetic or perforated tapes or the like. Thus, where the market demand has been such to justify the investments required to modify or construct such programmable devices, the versatility of operations that could be carried out has been limited only by the quantity and quality of intelligence that could be impressed on a program such as a magnetic or perforated tape or optically scannable medium. See, as examples, U.S. Pat. Nos. 3,502,044, 3,029,758 and 3,863,310.
While arrangements such as the foregoing are useful for their intended purposes, they suffer from the disadvantage that they in general require the wholesale replacement of existing equipment in order to take advantage of the flexibility and variety afforded by a program controlled work tool.
Is is an object of the present invention to provide power transmission apparatus, the output of which is readily controlled by a programmed source, yet which can be easily linked with an existing indexable tool. Additionally, the programmable power transmission of the present invention is capable of use in a wide variety of manufacturing applications where indexed tool operations are employed. Further, the apparatus of the present invention will afford all of the advantages attendant upon employment of a programmed source as the conrol medium for an indexable apparatus whether incorporated into existing machinery, or when forming the basis of entirely new manufacturing techniques.
To summarize the present invention, the apparatus includes a conventional indexing mechanism which converts continuous rotary power into intermittent rotary power which is continuously fed to oppositely rotating shafts. Dual coupling mechanisms are employed to transmit the output from one or the other of the rotating shafts to an output shaft. Selection of the coupling mechanism to be operated is preferably effected by solenoids which, in turn, are controlled by a program source such as a punched tape whereby the direction of rotation, period and, if desired, the speed of the output shaft is controlled by the program.
In a preferred embodiment, the output shaft is connected to a ball screw device which converts rotary motion to linear motion and the output of the ball screw device is connected to the shifting needle bar of a carpet tufting machine. With this arrangement, the number of patterns that can be formed in a tufted carpet can be made variable to an extent limited only by the capacity of the program. Also, the stitch pattern can be non-repeating along the length of the carpet which possibility was not available where cams or templates were used to obtain the shifting of the needle bar of the tufting machine.
The apparatus of the present invention can also be usefully employed with tools which work sheet material where the tool is translated laterally across the path of the material, for example, in cutting, stamping, folding operations or the like. Additionally, the apparatus of the present invention can be employed in sorting conveyed articles in a distribution facility where material, which may be either in liquid or solid form is to be passed from a source to a variety of work stations. Thus, for example, where containers are being fed from a storage facility to a variety of different filling machines having different capacities, the apparatus of the present invention can be employed to direct the required quantity of containers to selected machines according to a predetermined program. In this instance, the apparatus would function to divert the flow path of containers as is required.
The foregoing and other advantages and applications will become apparent as consideration is given to the following detail description of the invention and accompanying drawings, in which: